Variable pitch propeller



July 4, H, A, BERUNER 2,164,490

VARIABLE FITCH PROPELLER Filed Deo. 3, 1936 INVENTUR, Hf/VRY A BERN/v5@ Patented July 4, 1939 VARIABLE FITCH PROPELLER- Henry A. Berliner, Washington, D. C., assignor, by

mesne assignments,

to Engineering and Research Corporation', Riverdale, Md., a corporation of Maryland Application December 3, 19'36,.Serial No,` 113,964

8 Claims.

. tive and efficient pitch changing mechanism.

Another object of the invention is to provide novel pitch changing mechanism for a variable pitch propeller which is operated from the propeller shaft, which involves a minimum number of moving parts and which provides an extremely flexible control.

One propeller embodying the invention includes a ring gear surrounding and driven by the propeller shaft -and driving a bevel pinion. The pinion is rigidly connected to a shaft which lies substantially transverse to the propeller shaft and which is connected through a universal joint to a traction roller. A bearing member pivotal about an axis concentric with the universal joint supports a shaft which carries the roller so that the roller can be adjusted. The roller drivably engages a disc rotatable about the propeller vshaft and connected to a Worm which meshes with teeth on the propeller blade. Normally the roller `drives the ring at the same speed as the propeller shaft but to change the pitch the roller is adjusted to turn the ring either faster or slower than the shaft to turn the worm and rotate the propeller blade about its own axis.

Other objects, advantages and novel features of the invention will be apparent from the following description of the embodiment illustrated in the accompanying drawing, in which:

Figure l is a central section with parts in elevation of a propeller embodying the invention; and

Figure 2 is a view substantially on the line 2-2 of Figure 1.

The invention is illustrated as embodied in an aircraft propeller including a propeller shaft 4 carrying a hub 6 which is formed With a plurality of radial sockets 8. A blade I0 is journaled in each of the sockets 8 on bearings I2 and has its root end formed with gear teeth I4 meshing with a Worm I6 which is rotatably mounted in the hub 6. A worm .gear I8 is secured to each worm I6 and is adapted to be driven by a spiral tooth or a set of spiral teeth on a ring or disc 20 which is` mounted on bearings 22 for rotation about the axis of the propeller shaft. The mechanism so far'described is substantially similar to that more particularly described in my copending application Serial No. 92,823, filed July 27, ,1936, but it will be apparent that some other mechanism could (cl. 17o-163) be substituted if desired to connect the blade to the ring 2li.

Thering 20' is formed with a parti-toroidal surfacefor driving engagement with a traction roller v 24 which is rigidly secured to a shaft 26 journaled in a bearing member 28. The radially inner end of the shaft 26 carries a bifurcated yoke 30 forming a part of a gimbal type universal joint which includes a block 32 pivoted to the yoke 30 and a l similar yoke 34. The yoke 34 is carried by a shaft 36 supported by a bearing 38 mounted-on a fixed part 40 such as the engine housing. A bevel.;

. pinion 42 is secured to the shaft 36 and meshes with a ring gear 44 which is rigidly secured to the hub 6 to rotate therewith and with the propeller shaft 4. l In order to adjust the roller 24 thereby to change its point of engagement with the ring 20 to vary the driving ratio, the bearing member 28 is pivotally mounted on a pair of pivots 46 by means of bracket extensions 48. Preferably the pivots. 46 are coaxial with the center axis of thel universal joint so that the bearing member 28 can be moved Without affecting the shaft 3B. It wii\ .be apparent that movement of the member 28 about the pivots 46 will change the point of engagement of the roller 24 with the disc 20 to change the driving ratio therebetween, adjustment of the member 28 being effected either manually or automatically, as disclosed and claimed more particularly in my application Serial No. 92,823 referred to above.

The pivots 46 are carried by arms 41 pivotally mounted on a relatively stationary part of the engine or aircraft frame at 49 and compression springs 50 are mounted between said stationary part and the arms 4l. These springs serve to maintain a constant pressure between the rollers 24 and disc 20 to keep them in frictional driving engagement at all times. L

In order to disconnect the driving mechanism for changing the blade pitch, the arms 41 are connected to cables 52 which extend through conduits 54 to the pilots cockpit. The cables may be connected to a single operating lever or control by means of which the pilot may rock the arms 41 on their pivots against the force of springs 50 to move the roller 24 out of contact with the disc 20. Thus all driving force is removed and the mechanism will turn idly until the force on the cables 52 is removed so that the springs 50 can move the roller 24 back into contact with the disc 20. Rotation of the blades during disengagement of the roller from the disc can be prevented by designing the worm I6 to be non-reversing or. if

2 desired, a locking mechanism can be provided as shown in my copending application Serial No. 92,823. J

The gears 42 and 44 and the roller 2l are so.. proportioned that in operation the disc 20 will gagement of the roller 2l with the disc 20 will move radially outward to reduce the driving -ratio so that the ydisc ywill rotate slower. than the propeller shaft. .Thus there will be relative movement between the gear I8 and the ring 20 to turn the gear and the worm i6 thereby turning the 'blade in its socket, the speed at which the blade is turned being governed by the amount of movement of the member 28 from normal. When the blade has reached the desired new pitch, the member 28:.is moved back to its normal nposition thereby stopping further rotation of theblade. To rotateA the blade in the opposite direction for changing the pitch in the opposite sense, the member 28 'is moved counterclockwise, thereby causing the ring 20 to be driven. faster 4than the propeller blade.

It will be understood that the inventionjcan be applied to a propeller having two, three or even moreblades and that all of the blades will be adjusted simultaneously bythe same ring 2li. Various other modific tions might also be made, and` it is accordingly n t intended that the scope of the inventlon shall be limited to the form appended claims.`

What is claimed is:

l. In a variable .pitch propellerhaving a prot peller shaft and a blade, pitch changing mechanism comprising a ring'gear driven by the propeller shaft, a pinion meshing with said ring gear and driven thereby, a shaft secured to said, pinion, a fixed bearing supporting said shaft, a universal joint driven by said shaft, a traction roller driven by said universal joint,- an annular disc surrounding the propeller shaft and having toroidal surface engaging the edge of said roller, a worm engaging the propeller blade, meansconnecting said worni'to said disc to be driven thereby, and means to adjust said roller thereby to change the angie of the blade. i

2. In a variable pitch propeller having a propeller shaft and a blade, pitch changing mechanism comprising an annular disc surrounding the 55 propeller `shaft and drivablyconnected tothe propeller `blade,-a traction roller having its, edge engaging said disc, means supporting said roller for rotation about its axis, said means' being adjustable to yvary thepoint of engagement of 'the roller with the disc, an annular driving element surrounding and secured .to the shaft/,and a'I second shaft operable from said element and` member 28 is moved clockwise the point of en-` shown or otherwise thanby the termsof the the point of engagement of the roller with the disc, an annular driving element surrounding and secured to ythe shaft, andy means operable from said element todrlve-said shaft and roller.

4. In a variable pitch' propeller having a. prol peller shaft and a blade, pitch changing mechanism comprisingan annular disc surrounding the propeller shaft and drivably connected to the propeller blade, a traction roller having its edge engagingsaid disc, means supporting said 1o a *shaft rigidly secured ,to and supporting said 15 roller, a bearing assembly for rotatably supportL ing said shaft, a'secondshaft drivenfrom the` propeller shaft, a universal joint connecting the second shaft to said first named shaft, anda pivotal mounting for said bearing assembly cof axial with said universal joint. 5. In a variable pitch propeller having a shaft and a blade, pitch changing mechanism comprising an annular disc 'surrounding the propeller shaft and drivably connected tothe `blade, a traction roller having its edge drivably engaging said disc, means supporting said, roller for rotation about its axis, said means being adjustable to vary the bpoint of engagement of the rollerwith the" disc and tor move the roller into and out of engagement with the disc, meansl yieldingly urging' said supporting means toward the-disc to press the edge lof the roller into driving engage.-

' mentI therewith, means operable-at will to move by, pitch changing mechanism lcomprising an annular disc rotatably surrounding. the propeller shaftand ,having a driving surface formed on one of its faces, means Aconnecting `said vdisc-to the blade, an annular driving element surround- 5 ing and securedutofthe shaft, a second shaft drivably connected to said element and extendt ing outwardly from the propeller shaft, a roller having its edge drivably engaging said driving surface, means'for adjusting said rollerto varyjso its point of engagement with the driving surface, and means forming an adjustable driving connection between the roller and said second shaft..

7. In a variable pitch propeller having a propeller shaft and a blade -adjustably carried there- 5g by,`\pitch changing mechanism comprisingan annular disc rotatably surrounding the propeller" shaft and havinga driving surfacejformed on one-of its faces, means connecting said disc to peller shaft and a blade adjustably carried there- 40 the blade, an annular gear surrounding and se- 50" A cured to the propeller shaft, a`second`shaft extending outwardly from the propellergshaft and carrying a pinion meshing with said gear, a roller having its edge drivably engaging said driving -surface, means for adjusting' said roller to vary vtu; its point of engagement with the driving surface,

and means formingan adjustable driving cony nection between the rollerfand said second shaft.,

8. In a variable pitch propeller having a pro-` t peller shaft and a blade adjustably carried there- 70 by, pitch changing mechanism comprisingl an 70 the propeller shaft and drivably connected to the propeller blade, a traction roller having its edge engaging said disc; a shaft rigidly connected to said roller and supporting thesame, means including a bearing for supporting said shaft f .a and roller, said means being adjustable to vary shaft extendingv outwardly' from the propeller and outA of engagement with the driving surface and for varying its point of engagement with the driving surfsce, means yieldingly 4urging said last named-means in a diretion -to move the roller into driving nengagement with the driving surface, manually controllable mens to move the -roller out of engagement with the driving surface, and means forming an adjustabledriving connection )between the roller and said second shaft..

.HENRY'A BERLINER.l 

